A surface skimming laser is a semiconductor light emitting device of diverse and important applications as a result of the close proximity of the laser active region to the surface of the crystal, and the transverse or lateral injection of current into the structure from a diffused p-n junction.
See, for example, my paper in SPIE, Vol. 1582, Integrated Optoelectronics for Communication and Processing (1991), pages 194-205, and a commonly-owned USA patent in my name, U.S. Pat. No. 5,038,18 ('185), the contents of which paper and patent are herein incorporated by reference.
It is also well known that solid state sources offer unique advantages when used as illuminators for an electrooptic modulator or light valve for printing applications. See, for example, commonly assigned U.S. Pat. No. 4,786,918 ('918). A very desirable enhancement to the performance of this modulator can be achieved by fabricating two sources in close proximity, preferably on the same wafer, with a relative wavelength shift of several nanometers. By using dispersive elements, this wavelength shift can be converted into a linear relative displacement of the light spots in the image plane for the two sources, resulting in an angular displacement of the two beams in a plane beyond that of the beam scanning mechanism, thus enabling the two beams to be sent to different developing stations to facilitate multi-color Xerography. Although there is some wavelength shift that can be realized by varying the drive conditions of the semiconductor laser used in the modulator described in the '918 patent, the shift is in general not great enough for convenient design of the dispersive elements required for this increased performance device.
Moreover, the laser device described in said '918 patent is not of the laterally-injecting nor of the surface-skimming type and therefore does not offer the benefits of the surface-skimming-type laser described in my paper and the '185 patent.